Tipu Sensitive to Winter Cold in the Las Vegas Desert

Q. We purchased 11 Tipu trees in March of 2012.  We purchased these trees because they were recommended as fast growing trees for our property. Three of the 11 trees we planted died during the winter of 2012-13 and only growing “suckers” around the base of the trunks.  An arborist told us the trees were “toast” and recommended we might leave the suckers to regrow into a tree rather than remove them. Is there anything else we can do to help these trees or do you think they are a lost cause? 

Tipu showing regrowth from the base after winter kill due to low temperatures.

A. As you have already found out, this tree will freeze in our climate. This is what I believe killed the tops of your trees this past winter. According to Arizona State University it is hardy down to about 25°F. Temperatures below this cause winter leaf drop first followed by branch and trunk death as temperatures drop further.

            What you are seeing now is resprouting of the tree from the base which was protected from freezing temperatures by the soil. If the temperature had dropped even further you might have lost the entire tree with no regrowth from suckers.

            The arborist was right. You could select one of the stronger suckers and remove the rest. If you want a multi-trunked tree then leave three to five. These nurtured suckers will grow up to be a new tree that will promptly freeze to the ground again when temperatures drop to that 20ish F range.

            I am not in favor of growing this tree here and I will tell you why. This tree is originally from South America where it can reach heights of 100 feet with a 60 foot spread. In our harsh, desert climate it won’t get that tall but might reach 40 feet or so.

            In the wetter parts of California it has been used in water conservation landscapes. It is not a desert plant and should not be considered low water use and in the same category as acacias for instance. These trees should be considered moderate in their water use, similar to ash of a similar size.

            In some places they are considered invasive and their root systems destructive. This should not be the case here if you plant them several feet from walls, sidewalks, driveways and foundations. Plus, you should water them infrequently, not with shallow frequent irrigations and irrigate on sides away from structures to less damaging root growth.

            A lot of people in the warmer Phoenix area like this tree. There are a few who don't like the litter it produces and fear it's destructive potential. In a nutshell, because of its lack of cold hardiness, I do not believe it is suitable for the cooler climate of the Las Vegas Valley.